Timepiece including protective glass with antifogging device

Abstract

To provide a timepiece including a protective glass with an antifogging device.SOLUTION: A timepiece (10) includes a middle (11) closed by a rear lid (12) and a protective glass (13), wherein the timepiece (10) includes an antifogging device (100) for the protective glass (13), the antifogging device (100) includes: a transparent conductive oxide layer (105) provided on at least part of the inner face of the protective glass (13); and a thermal interface member (106) which has thermal conductivity of 1 W / m.K or more and is provided on the middle (11), in which a) the thermal interface member (106) secures heat exchange by contact between the conductive oxide layer (105) and the middle (11), and the middle (11) and the rear lid (12) are made of a heat conductive material, or b) the thermal interface member (106) secures heat exchange by contact between the conductive oxide layer (105) and the rear lid (12), and the rear lid (12) includes at least part (12a) made of a heat conductive material brought into contact with the thermal interface member (106).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a timepiece equipped with a protective glass having an anti-fogging device which prevents or limits the occurrence of fogging and microscopic water droplets on the inner surface of the protective glass. [Background technology]

[0002] Timepieces are routinely worn in environments that vary widely in terms of relative humidity, pressure and temperature. Although the construction of the timepiece prevents the ingress of moisture into the body, even if the timepiece is waterproof, gas exchange still occurs between the interior of the body and the external environment.

[0003] This gas exchange, called permeation, takes place through joints made mainly of polymeric materials with variable, but non-zero, permeability properties. Thus, in very hot and humid environments, water vapor may periodically enter the timepiece, which is not a problem in itself, since it will not be visible to the user, unless there is a visible haze on the inside of the protective glass.

[0004] Fogging occurs most frequently when the temperature to which the wearer is exposed drops, for example when swimming or entering an air-conditioned environment where the temperature is several degrees lower than before. Since the protective glass is the point of most contact with the external environment, it is natural that fine droplets of water due to condensation will adhere to the inner surface of the protective glass. Wearers often notice the presence of fogging on the inside of the watch and mistakenly think that the product is no longer waterproof. This phenomenon not only causes many product returns, but also causes a loss of user trust and a deterioration of the image of watch brands.

[0005] To prevent the adhesion of fine water droplets to the surface of protective glass, there are hydrophilic treatments that consist of applying a surfactant to the inner surface of the protective glass. These hydrophilic layers allow the water to spread over the entire inner surface of the protective glass and become invisible to the wearer. However, these hydrophilic layers are not always compatible with good aesthetics (coloration, diffusion effect, etc.).

[0006] Another method is based on the principle of absorbing the water contained in the steam entering the timer. However, these solutions are time-limited and have a limited absorption capacity (amount). As a result, these solutions are not entirely satisfactory. Summary of the Invention [Problem to be solved by the invention]

[0007] There is therefore a need to improve the anti-fogging capabilities of protective glasses and timepieces fitted with such protective glasses. [Means for solving the problem]

[0008] To this end, the present invention proposes a solution to the problems of the prior art by proposing a timepiece adapted with a protective glass equipped with a transparent anti-fogging device, which has excellent anti-fogging ability to prevent the occurrence of fogging in various use environments, the effect of which is not limited by time, nor by maximum absorption capacity.

[0009] In this context, the invention proposes a timepiece with a middle in which a watch movement is housed, the middle being closed by a back cover and a protective glass, said timepiece being characterized in that it comprises an anti-fogging device for the protective glass, said anti-fogging device comprising: a transparent conductive oxide layer provided on at least a part of the inner surface of the protective glass; - a thermal conductivity of 1 W / mK or more, and disposed in said middle; a) ensuring heat exchange by contact between the conductive oxide layer and the middle, the middle and the back cover being made of a thermally conductive material; or b) ensuring heat exchange by contact between said conductive oxide layer and a back cover, said back cover comprising at least one portion made of a thermally conductive material in contact with a thermal interface member; and a thermal interface member configured so as to

[0010] The anti-fogging device according to the invention makes it possible to obtain passive heating of the protective glass by utilizing the thermal conductive properties of the transparent conductive oxide layer and by bringing the transparent conductive oxide layer into contact with a back cover made of a thermally conductive material, in order to benefit from the body heat of the wearer when the timepiece is worn, so that the protective glass is no longer a cold spot of the timepiece.

[0011] Therefore, such an anti-fogging device is not time limited, nor is its anti-fogging capability limited.

[0012] The back cover is thermally conductive and is in contact with the wearer's skin, allowing heat exchange by "direct" conduction with the thermal interface member when the thermal interface member is in contact with the back cover, or by "indirect" conduction with the thermal interface member via the middle 11 made of a thermally conductive material when the thermal interface member is in contact only with the middle.

[0013] In addition to the characteristics mentioned in the previous paragraph, the timepiece according to the invention has the following additional characteristics, considered individually or in any technically possible combination: - the transparent conductive oxide layer is composed of tin-doped indium oxide, aluminum-doped zinc oxide, zinc oxide, or fluorine-doped tin dioxide; - The thermal interface member is a thermally conductive elastomer joint formed between the middle and the protective glass; - Thermally conductive elastomer joints are made of silicon or fluorosilicon based elastomers; - A thermally conductive elastomer joint seals the middle in the protective glass, - the thermal interface member is a thermally conductive pad housed in a recess in the middle; the thermally conductive pad is composed of one or more polymers, of metal, ceramic or carbon-based particles and / or of carbon fibres or of a mixture of these particles and / or fibres; - the thermally conductive pad is composed of particles of elastomer, preferably silicon, and ceramic; the thermal interface member is formed by a plurality of conductive pads; the thermal interface member is annular in shape; The present invention may have one or more of the following:

[0014] According to a first alternative embodiment of the present invention, the thermal interface member is a thermally conductive pad provided in the middle, which is in contact with the transparent conductive oxide layer and at least a portion of the back cover, ensuring heat exchange by conduction between the conductive oxide layer and the back cover.

[0015] In this first alternative embodiment of the invention, the timepiece may further comprise a system for positioning the thermal interface member, at least partially made from a thermal insulating material and configured to ensure thermal conduction between the back cover and the conductive oxide layer while insulating the thermal interface member from the middle.

[0016] According to a second alternative embodiment of the present invention, the thermal interface member is a thermally conductive pad provided on the middle, which is in contact with the transparent conductive oxide layer and the middle to ensure heat exchange by conduction between the conductive oxide layer and the middle. The middle and the back cover are made of a thermally conductive material to ensure heat exchange by conduction between the middle and the back cover.

[0017] In this second alternative embodiment, the middle can include a thermal insulating insert that prevents conduction and subsequent convection heat exchange between the external environment and the thermal interface member through the middle. Effect of the Invention

[0018] The objects, advantages and features of the present invention will become apparent from the following detailed description taken in conjunction with the following drawings. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic partial cross-sectional view of a first exemplary embodiment of a timepiece equipped with an anti-fogging device according to the invention. [Diagram 2]FIG. 2 is a schematic diagram of an alternative to the first exemplary embodiment shown in FIG. [Diagram 3] FIG. 3 is a schematic partial cross-sectional view of a second exemplary embodiment of a timepiece equipped with an anti-fogging device according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Unless otherwise noted, common elements are designated by the same reference numbers in all drawings.

[0021] FIG. 1 shows diagrammatically a partial cross-sectional view of a first exemplary embodiment of a timepiece 10 equipped with an anti-fogging device 100 according to the invention.

[0022] The timepiece 10, such as a wristwatch, is intended to be worn in contact with the skin of a wearer, for example on the wrist.

[0023] The timepiece 10 comprises a middle 11 intended to receive a timepiece movement 1 .

[0024] The timepiece movement 1 can be a mechanical, electromechanical or electronic movement. Preferably, the timepiece movement 1 is a mechanical movement.

[0025] The middle 11 is closed at the bottom by a back cover 12 and at the top by a protective glass 13 to protect the watch movement 1 .

[0026] Timepiece 10 further comprises a flexible or articulated bracelet (not shown), both ends of which are intended to be removably coupled to, for example, middle 11 via an ad hoc fastening system not described in this application, so that a user can wear timepiece 10, for example on the wrist, with the outer surface of back cover 12 in contact with the wearer's skin.

[0027] The back cover 12 has at least one portion 12a made of a thermally conductive material, such as a metal and / or ceramic and / or a carbon fiber filled polymeric material, which portion 12a is adapted to contact the wearer's skin.

[0028] Preferably, the back cover 12 is made entirely of a thermally conductive material, preferably a metal and / or ceramic and / or carbon fiber filled polymer based material.

[0029] Generally speaking, for the purposes of this application, a thermally conductive material is considered to have a thermal conductivity of 1 W / mK (watt per meter Kelvin) or greater.

[0030] Preferably, the back cover 12, or at least this part 12a of the back cover 12, is made from a thermally conductive material having a thermal conductivity of more than 10 W / mK.

[0031] The timepiece 10 further comprises an anti-fogging device 100 for the protective glass 13 in order to prevent the formation of fogging on the inner surface of said protective glass 13, i.e. the surface facing the watch movement 1, or to limit / reduce the presence of visible fogging after a large thermal shock.

[0032] For this purpose, the anti-fogging device 100 comprises a layer 105 of transparent conductive oxide (TCO) applied directly to at least a part of the inner surface of the protective glass 13 .

[0033] Advantageously, the transparent conductive oxide layer 105 is provided over the entire inner surface of the protective glass 13 .

[0034] If the transparent conductive oxide layer 105 is provided on part of the inner surface of the protective glass 13, the transparent conductive oxide layer 105 must be sufficiently extensive to ensure that the protective glass 13 can be heated and prevented from fogging.

[0035] This transparent conductive oxide layer 105 has thermal and conductive properties that make it suitable for use in the anti-fogging device 100 according to the invention.

[0036] Preferably, the transparent conductive oxide layer is deposited on the protective glass 13 by chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods, however other thin film deposition methods known to those skilled in the art are also possible.

[0037] The transparent conductive oxide layer 105 is composed of, for example, tin-doped indium oxide, aluminum-doped zinc oxide, zinc oxide, or fluorine-doped tin dioxide.

[0038] The anti-fog device 100 further comprises a thermal interface member 106 provided on the middle 11 and configured to bring the transparent conductive oxide layer 105 into thermal contact by conduction with the back cover 12 or, if the back cover 12 is not entirely made of a thermally conductive material, with at least the thermally conductive portion 12a of the back cover 12.

[0039] Alternatively, as shown in FIG. 2, the thermal interface member 106 can be configured to bring the transparent conductive oxide layer 105 into thermal contact with the middle 11 by conduction if the middle 11 is made of a thermally conductive material, which then provides heat exchange with the back cover 12, or a thermally conductive portion 12a of the back cover 12.

[0040] If desired, the thermal interface member 106 can be made of a material that is electrically insulating yet promotes heat exchange by conduction.

[0041] The thermal interface member 106 is, for example, a thermally conductive pad having a thermal conductivity of 1 W / mK or greater, and preferably greater than 2 W / mK.

[0042] The thermal interface member 106 is disposed in a recess in the middle 11, for example via a disposition system.

[0043] Such an arrangement system may, for example, include an insulating element or be made entirely of insulating material to insulate the thermal interface member 106 from the middle 11 and promote thermal conduction between the back cover 12 and the transparent conductive oxide layer 105 while preventing heat loss by conduction with the middle 11, which is in contact with the external environment.

[0044] The thermal interface member 106 is, for example, a thermally conductive pad composed of one or more polymers, for example, an elastomer, and metal, ceramic, or carbon-based particles and / or carbon fibers, or a mixture of these particles and / or fibers.

[0045] The thermal interface member 106 is, for example, a thermally conductive pad composed of silicon and metal and / or ceramic particles.

[0046] The thermal interface member 106 is, for example, a thermally conductive pad having an annular shape so as to contact the transparent conductive oxide layer 105 at the periphery of the cover glass 13 and the back cover 12 .

[0047] The thermal interface member 106 may be formed by a plurality of thermally conductive pads distributed inside the middle 11 to generate a plurality of thermal conduction points between the back cover 12, the portion 12a of the back cover 12, or the back cover 12 and the transparent conductive oxide layer 105.

[0048] As shown in FIG. 1, a sealing joint 17 may be provided between the protective glass 13 and the middle 11 to ensure the waterproofness of the timepiece 10 .

[0049] The anti-fogging device 100 according to the invention utilizes the body heat of the wearer to passively heat the protective glass 13 by conduction when the timepiece 10 is worn.

[0050] The back cover 12 is thermally conductive and in contact with the wearer's skin, allowing heat exchange by "direct" conduction with the thermal interface member 106 when the thermal interface member 106 is in contact with the back cover 12, or by "indirect" conduction with the thermal interface member 106 via the middle 11 made of a thermally conductive material when the thermal interface member 106 is in contact only with the middle 11.

[0051] The thermal interface member 106 also ensures heat exchange by conduction with the transparent conductive oxide layer 105 in order to eliminate any cold spots that may be present on the protective glass 13 .

[0052] Thanks to the invention, the cold spot is no longer located on the protective glass 13. As a result, if fog occurs, it will occur elsewhere in the cold zone, which is not visible to the wearer, for example under the dial.

[0053] FIG. 3 illustrates a second exemplary embodiment of the present invention.

[0054] In this second exemplary embodiment, the thermal interface member 106' is a thermally conductive elastomeric joint arranged between the protective glass 13 and the middle 11, which joint must be made of a thermally conductive material or, in the second embodiment, have a thermally conductive internal part so as to be able to exchange heat with the back cover 12 or with the thermally conductive part 12a of the back cover 12.

[0055] In this second exemplary embodiment, the thermal interface member 106 ′ also provides a watertight seal between the cover glass 13 and the middle 11 .

[0056] The thermally conductive elastomer joint forming the thermal interface member 106' is, for example, a silicon-based or fluorosilicon-based elastomer.

[0057] The thermally conductive elastomeric joint forming the thermal interface member 106' may be filled with, for example, a metallic material (eg, aluminum), carbon (eg, graphite), a ceramic material, or a mixture thereof. [Explanation of symbols]

[0058] 1. Watch Movements 10 Clock 11 Middle 12 Back cover 12a Thermally conductive part 13 Protective glass 17 Seal joint 100 Anti-Fog Device 105 Conductive oxide layer 106 Thermal interface components 106' Thermal interface member

Claims

1. A timepiece (10) comprising a middle (11) closed by a back (12) and a protective glass (13), characterized in that the timepiece (10) comprises an anti-fogging device (100) for the protective glass (13), the anti-fogging device (100) comprising: a transparent conductive oxide layer (105) provided on at least a part of the inner surface of said protective glass (13); - having a thermal conductivity of 1 W / m.K or more and provided in the middle (11); a) ensuring heat exchange by contact between said conductive oxide layer (105) and said middle (11), said middle (11) and said back cover (12) being made of a thermally conductive material; or b) ensuring heat exchange by contact between said conductive oxide layer (105) and said back cover (12), said back cover (12) comprising at least one portion (12a) made of a thermally conductive material in contact with a thermal interface member (106); and the thermal interface member (106) configured as above.

2. 2. The timepiece (10) according to claim 1, characterized in that the transparent conductive oxide layer (105) is made of tin-doped indium oxide, aluminum-doped zinc oxide, zinc oxide, or fluorine-doped tin dioxide.

3. 2. The timepiece (10) according to claim 1, characterized in that the thermal interface member (106) is a thermally conductive elastomer joint provided between the middle (11) and the protective glass (13).

4. 4. A timepiece (10) according to claim 3, characterized in that said thermally conductive elastomeric joint is made of an elastomer based on silicon or fluorosilicon.

5. 5. The timepiece (10) according to claim 4, characterized in that the thermally conductive elastomeric joint seals the middle in the protective glass (13).

6. 2. The timepiece (10) according to claim 1, characterized in that the thermal interface member (106) is a thermally conductive pad housed in a recess in the middle (11).

7. 7. A timepiece (10) according to claim 6, characterized in that the thermally conductive pad is made of polymer-based and metallic, ceramic or carbon-based particles and / or carbon fibres, or a mixture of these particles and / or these fibres.

8. A timepiece (10) according to claim 7, characterized in that the thermally conductive pad is made of an elastomer system, preferably of silicon system, and is made of ceramic particles.

9. The timepiece (10) of claim 6, wherein the thermal interface member (106) is formed by a plurality of conductive pads.

10. The timepiece (10) of claim 6, wherein the thermal interface member (106) has an annular shape.

11. 2. The timepiece (10) according to claim 1, characterized in that the timepiece comprises a system for positioning the thermal interface member (106) configured to ensure thermal conduction between the back cover (12) and the conductive oxide layer (105) while insulating the thermal interface member (106) from the middle (11).

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